>> reporter: the harvard law professor who's never run for political office designed the president's consumer financial protection bureau. she's cultivated a reputation as a wall street watchdog. >> i'm not a professional politician. i got in this race because working families and little businesses have been drawing the short end of the stick for far too long now. and washington is rigged to work for big oil, to work for wall street. >> reporter: there are a lot of people on wall street who do not want to see you in office. >> they've made that pretty clear! and they have sent lots of money to scott brown, millions of dollars, and, look, scott brown's been working with the folks on wall street for a long time. >> reporter: wall street is republican senator scott brown's biggest contributor. the financial sector donated more than $2.5 million to his reelection campaign. but in 2010, brown cast the tie- breaking vote to pass wall street reforms. >> i don't owe anybody anything because nobody helped me get down there except the people of massachusetts. >> reporter: the 53-year-old is a